Exosomes are lipid-bilayer enclosed vesicles with diameters of 30–150 nm, which play a pivotal role in cell communication by transporting their cargoes such as proteins, lipids, and genetic materials. In recent years, exosomes have been under intense investigation, as they show great promise in numerous areas, especially as bio-markers in liquid biopsies. However, due to the high heterogeneity and the nano size of exosomes, the separation of exosomes is not easy. This review will deliver an outline of the conventional methods and the microfluidic-based technologies for exosome separation. Particular attention is devoted to microfluidic devices, highlighting the efficiency of exosome isolation by these methods. Additionally, this review will introduce advances made in the integrated microfluidics technologies that enable the separation and analysis of exosomes.

Precise micro-grinding machining was proposed to fabricate regular and controllable micro-grooved array structures on the surface of mold cores to realize the mass production and manufacturing of micro-structured polymer components by micro injection molding in this paper. First, the 3D topographies and section profiles of micro-ground mold cores and micro-formed polymers with different micro-structure parameters were presented. Then, the surface roughness of mold cores and polymers were compared. Next, the relationships between machining accuracy of mold core ground by micro-grinding and filling rates of micro-structured polymer formed by micro injection molding were investigated. Finally, the influences of micro injection molding parameters on the filling rate of micro-structures polymer were investigated. It is shown that the micro-structured polymer can be effectively and rapidly fabricated using the proposed method. The experimental results indicate the highest form accuracy of the micro-grooved mold core and the filling rate of micro-structured polymer can reach to 4.05 µm and 99.30%, respectively. It is found that the filling rate of the micro-structured polymer roughly increased with increasing machining accuracy of the mold core. The injection pressure had the greatest influence on the filling rate of the injection formed polymer, while the melt temperature had the least influence.

Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties, corrosion resistance and good biocompatibility. However, problems such as rejection, shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface. The structures with specific functions, which can enhance osseointegration and antibacterial properties, are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues. This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants. The applications of surface functional structure on different titanium and titanium alloy implants are introduced, and their manufacturing technologies are summarized and compared. Furthermore, the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail. Finally, the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined, and recommendations for future research are presented.